Some time ago, I was helping clean up at a construction job site, and I was struck by the amount of foam insulation that had been trimmed off and discarded when they were fitting it into the building. I picked up a large piece and experimentally carved it with my pocket knife. I was surprised by how easily it could be formed into a variety of shapes. Being your average, normal modeler (i.e., on a very tight budget), this seemed very promising to me. I checked at a number of building supply stores and found that this ‘blue foam’ can be purchased in a variety of sizes and thickness for a surprisingly low cost, at least in the United States.
The blue foam is Dow polystyrene styrofoam, and it comes in R-3 1/2″ and R-4 3/4″ thick sheets. The sheets are 4′ x 8′ and normally cost under $10.00 per sheet. This size yields enough material for a quite a few scratchbuilding projects.
I was building the Ertl/AMT starship models of USS Enterprise, and a Klingon battle cruiser from the original Star Trek series for a friend. He wanted to know if it would be possible to add an additional, scratchbuilt ship; so the goal became to build a three-ship display of the USS Enterprise, a Klingon battle cruiser, and the Romulan Bird of Prey. My friend liked the very small scale (1/2200), three-ship Ertl/AMT model set that I’d built previously. He wanted to duplicate this set with the larger models, which meant I would have to scratchbuild the Romulan ship. Granted, if you look very hard, it is possible to find the Romulan model kit, but I have only rarely seen it and always expensively priced. Blue foam to the rescue!
With the blue foam, I had previously scratchbuilt the submarine Stingray from the Gerry Anderson TV series, and a 1/2500 scale Enterprise-D as a companion to the model of Deep Space Nine. I already had the smaller, three-ship set by Ertl/AMT, as well as the original Klingon ship and the Enterprise.
I also had a set of the MicroMachines original series starships (1/7600 scale?) and was able to borrow some Star Trek reference books for views of the ships. I put together working drawings using this method: The scale of the scratchbuilt Romulan Bird of Prey had to be 1/635. The small AMT three-ship set and the MicroMachines ships all seemed to be proportionally scaled to one another, so I felt I could make reasonable sizing assumptions based on the smaller ships. I measured them out against the already built 1/635 scale ships and came up with workable data to build from. This method may horrify some of the precision model builders out there, but it worked for me. I wanted the completed model to be accurate, but having it “look about right” visually is much more important as far as I am concerned. Drawings completed, it was time to start cutting foam.
Working the Foam:
I used a wide variety of cutting implements to carve the foam, but the tool that got used the most by far is a large, snap-off blade razor cutter. I used the drawings to make cardboard templates, broken down into sections (main hull, port and starboard wings, engines nacelles, upper hull, and tail fin). WARNING! Two major points to remember: (1) it is quite easy to cut yourself badly when using any kind of edged tool, so please be careful, and (2) cutting and carving this foam is exceptionally messy, especially when you get to the sanding phase. If you keep the expected mess in mind before getting started, you’ll pick a work area where clean up will be much easier.
I used the cardboard templates to draw the ship sections directly on the foam, which in turn allowed me to cut right on the lines. Another caution–the foam is, well, styrofoam. A truly impressive number of inks, chemicals, and paints can and will cause it to dissolve before your eyes. Always experiment on a scrap piece with your marking pens and paints. I used a Uni-ball Microfine to draw my lines when trials showed that it didn’t dissolve the foam.
A number of white glues work very well with this foam. Sobo, Elmer’s, and Weldbond are favorites of mine. For this starship, I used Weldbond exclusively, as it has a rapid drying time compared to the other white glues and dries very clear. Regular tube glues and liquid cements tend to eat the foam, as do most super glues.
I used pieces from a number of thick metal wire coat hangers in places where I needed to join parts (like wings or engines) to each other. The Weldbond keeps everything attached where it’s supposed to be, but having the coat hanger sections buried inside the parts adds greatly to the model’s structural strength.
I used drywall patch sanding screens to gently sand and shape the foam. I do not know what grit the drywall screen is, but it seems comparable to 300 grit. It is possible to shape most of the rough details on the model this way. The undercut at the bottom rear of the starship was first whittled out with the razor and then sanded down. I recommend wearing a dust mask when sanding, as this stuff goes everywhere! The wings were given rough leading edge tapers, which I then sanded to shape.
The front of the engine nacelles were also rough formed with the razor and then very carefully sanded into a rounded shape. The upper hull/bridge section was angle-cut around the entire vertical sides to have the proper degree of slant and then lightly sanded. The tail fin was cut from 1/2″ foam using the proper template, and then I sectioned it in half along its long measurement to make it more to scale.
To fill in the inevitable gaps that occur (plus minor mistakes from the edge of the sanding screen), I used Patch-N-Paint Lightweight Spackling, from Custom Building Products. It doesn’t shrink, it doesn’t eat the foam, and it dries very fast, usually within 15 minutes. Of course, the thicker it’s applied, the longer it will take to dry. I also used the spackling to very lightly coat the entire model. It serves as a barrier to protect the foam from the paint, but you must sand it smooth after it has dried.
The paint job makes the Romulan Bird of Prey unique, and it may seem daunting to attempt without decal assistance. But, really, it just looks hard, and you won’t find it that difficult to do.
The first step is priming the ship. Again, test your choice of paints on scrap foam first! You don’t want to get this far only to watch your favorite primer melt the foam model into slag!
For a safe primer coat, I used Krylon Living Color Latex Enamel. Heather Gray makes a good basic primer, as does the glossy white. For this model, I had the added advantage of being able to prime the starship with the Heather Gray and use it as the top coat as well.
I sprayed straight out of the can, misting on multiple light coats to avoid drips. Allow a minimum of one hour drying between the coats. I sprayed on at least six light coats of the Krylon over the entire model to “prime” the foam. If you miss covering a spot and later use an enamel paint, it will eat holes in your model at that spot.
Once the top coat of paint has dried overnight, it’s time to tackle the bird design. Using a pencil, I copied the outline of the bird from the MicroMachines Bird of Prey, and lightly drew it on the belly and wings of the starship, including the engine nacelles. I followed this very carefully with black paint and allowed it to dry. After that, you need to mask the ship so that only the area inside of the black lines is showing. Then paint in the orange (Testors gloss enamel 1127 orange, thinned at a ratio of 2 parts thinner to 1 paint) and allow it to dry overnight before unmasking the ship. I highly recommend Scotch Safe-Release Masking Tape (No. 2070). With the same black paint used to make the bird outline, draw in the feathers, feet, body, and beak.
After giving everything time to dry thoroughly, I added the topside details with paint. There are 15 dots arrayed on the upper hull (sensors? Chocolate covered manhole covers?) and lots ‘o dots on the sloped sides of the bridge, randomly spaced. I assumed 2 decks for the bridge portion of the hull, and 3 decks for the lower, main hull; a random window pattern was used here as well. And I placed a large circle/dot at the very front of the ship as I assumed a bow-mount for the plasma weapon. After the dots dry, coat the entire ship with Future floor polish to protect the paint.
Foam is great stuff to work with as long as you keep its limitations in mind. I’ve build submarines, tanks, and costume props out of this foam, and while you need to be careful with the finished model, the material is surprisingly durable. As I’m still learning what can be accomplished with this inexpensive, versatile foam, I would be delighted to see feedback from other modelers experiences with it. Give it a try!
R-4 Residential Sheathing Extruded Polystyrene Insulation
Dow Chemical Company
Midland, MI 48674
Frank T. Ross & Sons, Inc.
P.O. Box 522
Richmond, IL 60071
Patch-N-Paint Lightweight Spackling
Custom Building Products
Seal Beach, CA
Solon, OH 44139
Low-tack masking material:
3M Commercial Office
St. Paul, MN 55144-1000